The present application relates to an information processing device, a communication control method and a program.
Recently, an information processing device capable of performing contactless-type communication with a reader/writer (or an information processing device having a reader/writer function) such as a contactless-type integrated circuit (IC) card, a radio frequency identification (RFID) tag and a cell phone on which a contactless-type IC chip is mounted becomes widely used.
The reader/writer (or the information processing device having the reader/writer function, similarly hereinafter) and the information processing device such as the IC card and the cell phone use a magnetic field (carrier) of a specific frequency such as 13.56 MHz in communication. Specifically, the reader/writer transmits the carrier on which a carrier signal is put, and the information processing device, which receives the carrier by an antenna, returns a response signal to the carrier signal received by load modulation, and by this, the reader/writer and the information processing device perform the communication.
Also, the information processing device capable of performing the contactless-type communication with the above-described reader/writer may safely transmit/receive and update data of which falsification becomes issue, such as electronic money, by including a tamper-resistant IC chip. Therefore, a variety of services using the information processing device on which the IC chip capable of performing the contactless-type communication with the above-described reader/writer is mounted is socially widely provided. Then, with spreading of the service provision, the information processing device on which the contactless-type IC chip is mounted such as the IC card and the cell phone becomes more widely used.
In such a circumstance, a wide variety of techniques regarding the contactless-type communication are developed. As a technique to perform the communication with a communication distance defined by distance specification information by changing a Q value of the antenna based on the distance specification information to define the communication distance, there is Japanese Patent Application Laid-Open No. 2005-323178, for example. Also, as a technique to prevent excessive increase in temperature of the IC chip by changing the Q value of the antenna according to the temperature of the IC chip, there is Japanese Patent Application Laid-Open No. 2005-11009, for example.
The reader/writer (or the information processing device having the reader/writer function; hereinafter, referred to as the “reader/writer” as a matter of convenience) and the information processing device such as the IC card and the cell phone perform the contactless-type communication using the magnetic field (hereinafter, referred to as the “carrier”) of the specific frequency such as 13.56 MHz, for example. More specifically, the reader/writer transmits the carrier on which the carrier signal is put, and the information processing device, which receives the carrier by the antenna, returns the response signal to the carrier signal received by the load modulation. The reader/writer demodulates the above-described response signal by detecting an amplitude change of a voltage at an antenna end generated by the load modulation, for example. The contactless-type communication is performed in the above-described manner, for example, between the reader/writer and the information processing device. As a communication speed in the communication using the carrier between the reader/writer and the information processing device, there are various speeds such as 106 [kbps], 212 [kbps], 424 [kbps] and the like. Also, the above-described communication speed depends on the communication function included in the reader/writer and the information processing device, for example.
The above-described difference in the communication speed is presented in a size of the voltage of the carrier signal at the antenna of the reader/writer, for example. More specifically, when the Q value of the antenna of the reader/writer is a certain value (constant value), for example, the faster the communication speed is, the smaller the size of the voltage corresponding to the carrier signal in the antenna is. Herein, the above-described phenomenon also applies to the information processing device for transmitting the response signal by performing the load modulation, for example. The above description indicates that the faster the communication speed is, the lower the stability of the communication between the reader/writer and the information processing device becomes, for example.
Herein, a related art that performs the communication with a communication distance defined by the distance specification information (hereinafter, also referred to as “a related art 1”) switches the Q value of the antenna for performing the communication with the communication distance defined by the distance specification information. By changing the Q value of the antenna, the reader/writer and the information processing device to which the related art 1, for example, is applied might be able to stabilize the communication with the communication distance defined by the distance specification information. However, the related art 1 merely changes the Q value according to the communication distance defined by the distance specification information based on a user input, for example. Also, the related art 1 does not make consideration at all of lowering of the stability of the communication due to the communication speed between the above-described reader/writer and information processing device. Therefore, even when the related art 1 is used, the stabilization of the communication is not realized when the reader/writer and the information processing device perform the communication at a higher communication speed with a certain communication distance, for example.
Also, the information processing device to which the related art to prevent the excessive increase in temperature of the IC chip (hereinafter, also referred to as a “related art 2”) is applied merely changes the Q value of the antenna according to the temperature of the IC chip. Also, this does not make consideration at all of the lowering of the stability of the communication due to the communication speed between the above-described reader/writer and information processing device. Therefore, even when the related art 2 is used, the stabilization of the communication between the reader/writer and the information processing device is not realized.